The present invention relates generally to the field of dispensing machines for propane tanks.
Propane is a liquefied petroleum gas and is stored in a variety of tanks for use in industrial and residential use. Upon exiting the pressurized tank, the propane changes state from a liquid to gas. The residential application of propane includes use as a fuel for cooking grills and a variety of appliances. The U.S. Department of Transportation has established standards for the tanks which are referred to as D.O.T. containers or cylinders. One such tank 20, illustrated in FIG. 1, includes a cylindrical and hollow main body 21 having a rounded bottom end resting upon and fixedly attached to a ring 22. The ring provides a base for tank 20 to rest. Gas within the tank is controllably released via a standard, commercially available, gas valve 23 mounted atop the tank. A valve safety wall or collar 24 is fixedly mounted atop the tank and partially surrounds valve 23. A plurality of slots or openings 25 are provided in wall 24.
A current practice is for the user to take an empty propane tank to a tank servicing location, such as a grocery store, a gasoline filling station or other retail establishment, and to trade in the empty tank for a propane filled tank. Generally, the propane servicing is provided by the retail establishment as a sideline with the tanks being stored externally of the building for safety reasons. Tanks typically are stored in a steel mesh cage and may also include a central supply of propane utilized to fill the smaller tanks. Thus, the current procedure is for the retail salesman to take time away from the principal business, exiting the building, unlocking and then opening the tank storage cage and inserting the empty tank while retrieving a propane filled tank. In the meantime, additional retail personnel are required within the building to service the principal customers and to monitor the checkout lines. What is needed is a personnel-free, automatic machine for receiving the empty tanks and for dispensing propane filled tanks. Disclosed is such a combination and method.
Vending machines are known for dispensing tanks of compressed gas such as shown in U.S. Pat. No. 5,829,630 issued to Fernald and U.S. Pat. No. 4,778,042 issued to Warren et al. An automatic dispenser of liquefied gas bottles is disclosed in the French Patent 2641-887-A. Disclosed herein is a fluid control system that unlocks individual lockers containig filled propane tanks. Fluid operated sensors associated with each locker detect if the locker door is closed after the propane tank is removed, further detect the presence of a tank within a locker and whether the tank in the locker is filled or unfilled.
One embodiment of the present invention includes a frame forming a plurality of individual lockers each for holding a propane tank. Doors are mounted to the frame adjacent each of the lockers. Fluid operated locks are mounted to the frame and engageable between the frame and the doors to lock the doors in the closed positions. Fluid operated weight sensors are mounted to the frame within each of the lockers to measure the weight of a tank positioned within a locker. A plurality of fluid lines extend from the locks and the sensors to a source of pressurized fluid. A control apparatus controls fluid flow to the locks for activation thereof and to receive data from the fluid operated weight sensors for determination of the presence of a filled or unfilled tank.
Another embodiment of the present invention includes a method of dispensing propane tanks comprising the steps of inserting a plurality of filled propane tanks into a plurality of lockers, and closing the door for each of the plurality of lockers. An unlocking command is sent via a fluid line from a control apparatus to a fluid operated lock. The selected propane tank is removed from the particular locker and data is sent to the control apparatus via the fluid line connected to a fluid operated tank sensor of the particular locker. The data corresponds to whether a filled or unfilled tank is present in the particular locker.
It is an object of the present invention to provide a combination of propane tanks and a machine for automatically dispensing the tanks.
In addition, it is an object of the present invention to provide a new and improved method for dispensing tanks of propane.
Another object of the present invention is to provide a dispenser of propane tanks in plurality of lockers each having fluid operated door locks, door sensors and tank sensors.
Related objects and advantages of the present invention will be apparent from the following description.